Evaluated Kinetic, Photochemical and Heterogeneous Data for Atmospheric Chemistry: Supplement V.   IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry

Abstract

This paper updates and extends previous critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992)]. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 658 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available data on enthalpies of formation of the reactant and product species. We have also included for the first time in this series of evaluations a section on heterogeneous reactions of importance in atmospheric chemistry. Key words: air pollution; atmospheric chemistry; chemical kinetics; data evaluation; gas phase; heterogeneous atmospheric reactions; photoabsorption cross-section, photochemistry; quantum yield; rate coefficient.

Rate constants for the reaction of NO and HO2 with peroxy radicals formed from the reaction of OH, Cl or NO3 with alkenes, dienes and α,β-unsaturated carbonyls

“…The NIST reaction data base (NIST standard reference data 17 version 7.0, web version public release 1.1) (NIST, 2000) was used to provide values of rate constants for the reactions of HO 2 and NO with organic peroxy radicals with which to determine the values of m and c. If more than one determination of a rate constant existed the IUPAC recommendation (2001 web version December 2001) based on evaluations (Atkinson et al, 1997a;Atkinson et al, 1997b;Atkinson et al, 1999;Atkinson et al, 2000;Atkinson et al, 1997c) was used, otherwise the values were simply averaged. The database presented here is considerably larger than the previous work.…”

“…Wallington et al, 1994) Note where the reference is given as IUPAC it refers to the IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry Dec 2001, which is based on the original references (Atkinson et al, 1997a;Atkinson et al, 1997b;Atkinson et al, 1999;Atkinson et al, 2000;Atkinson et al, 1997c). .…”

A comprehensive modeling study of iso-octane oxidation

“…In addition, in their review, Atkinson et al [63] The reverse decomposition rate constants are calculated from microscopic reversibility. We assume that any C 8 H 17 Ȯ 2 radical, with 75 (3N-6) vibrational modes, is rapidly stabilized to its ground state, so the energy released during C-O bond formation is easily dissipated throughout the molecule.…”

Are Vibrationally Excited Molecules a Clue for the “O3 Deficit Problem” and “HOx Dilemma” in the Middle Atmosphere?

“…By noting a coincidence between maxima in measured OH concentrations (as usual, this will be denoted by square brackets embracing the chemical species, in this case [OH]) and the ozone observations, they suggested that a good correspondence between the ozone production and destruction rates could be obtained if a downward revision in the rate constant of reaction 3 could be done. However, the proposed downward revision by 50 to 70% lacks support both from theoretical [11][12][13] and recommended 14 data while leading to large underestimates of the observed abundances 6 of OH and HO 2 . In turn, Sandor and Clancy 15 found that ground-based microwave measurements of HO 2 concentrations at 50-80 km altitudes were 23-47% higher than photochemical model values at mid day, agree with model values at 0900 local time, and exceed model mixing ratios by 70-100% immediately after sunset.…”

“…However, [H] is rather small up to 40 km reaching at 55-60 km the value of [OH] reported in the literature, 1 which attains its maximum value close to 65 km (see ref 9 and section 3.2 for a somewhat different representation). The y ) 0 and 1 mechanisms should therefore be considered together in the upper stratosphere and mesosphere (given the relatively small rate constant 14,33,34 of the HO 2 + O 3 reaction, we ignore at this stage the mechanism involving y ) 2).…”